1. Field of the Invention
The invention relates to a filter and a coil connecting frame thereof, and in particular to a modulized filter and a coil connecting frame thereof.
2. Description of the Related Art
In order to manufacture electronic devices precisely, a surface mount device (SMD) is typically used in printed circuit boards to join electronic elements thereon. Conventionally, there are two methods of manufacturing magnetic elements described in the following.
One method of manufacturing conventional magnetic elements is winding a copper line on an iron core to form a coil, and one end of the coil is fixed on a pad of the printed circuit board by soldering. Also, a surface mount device (SMD) element is simultaneously attached to the printed circuit board. Pins for electrically connecting to an external apparatus are then fixed in insertion holes by soldering. The coil is covered with a silica gel. The printed circuit board and the electronic elements thereon are finally packaged by an epoxy resin.
However, as the density of the coil increases, the number of coils which require soldering increases. Because the coils are manually soldered, increasing the number of coils becomes difficult. Soldering must be performed several times to fix all the coils, which causes time consuming and decreases magnetic element quality. Moreover, the pins are manually inserted into the insertion holes. As the density of the coil increases, the number of manually inserted pins also increases, resulting in difficult assembly such as length inconsistency of the pins or tilted angles of the pins. Moreover, the gluing of the magnetic elements is performed manually so that the amount of the glue is difficult to ensure its uniformity, thereby reducing quality of the products. When the wrong percentage of the glue is used to package the magnetic elements, the poor quality suffers.
Another method of manufacturing conventional magnetic elements is winding a copper line on an iron core to form a coil, and then the coil is embedded within a lead frame so as to form a surface mount device (SMD) transformer module. The surface mount device (SMD) transformer module and related electronic elements are attached on the printed circuit board. Pins for electrically connecting to an external apparatus are then fixed in insertion holes by soldering. Finally, a shell to contain the printed circuit board is packaged by gluing.
However, because the solder contains a high lead content, thus these kinds of surface mount device (SMD) transformer modules do not comply with environmental regulation requirements. Recently, high density electronic elements are disposed in electronic devices to limit the size of the surface mount device (SMD) transformer module, which results in low reliability, low yielding, high cost and frequent failure of the surface mount device (SMD) transformer module. Similarly, high density electronic elements reduce the interval between two pins, thus increasing the possibility of electrical failure and reducing high voltage resistance.
In view of this, it is one important subject of the invention to provide a filter and a coil connecting frame to solve above-mentioned problems.